EP0214824B1 - Procédé de fabrication d'un elément de mémoire optique - Google Patents

Procédé de fabrication d'un elément de mémoire optique Download PDF

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Publication number
EP0214824B1
EP0214824B1 EP19860306711 EP86306711A EP0214824B1 EP 0214824 B1 EP0214824 B1 EP 0214824B1 EP 19860306711 EP19860306711 EP 19860306711 EP 86306711 A EP86306711 A EP 86306711A EP 0214824 B1 EP0214824 B1 EP 0214824B1
Authority
EP
European Patent Office
Prior art keywords
substrate
resist film
mask
photo
memory element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19860306711
Other languages
German (de)
English (en)
Other versions
EP0214824A3 (en
EP0214824A2 (fr
Inventor
Kenji Ohta
Junji Hirokane
Akira Takahashi
Tetsuya Inui
Shohichi Katoh
Toshihisa Daiya-Heights Deguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP19293785A external-priority patent/JPS6252741A/ja
Priority claimed from JP60207864A external-priority patent/JP2534226B2/ja
Priority claimed from JP60215909A external-priority patent/JPS6273440A/ja
Application filed by Sharp Corp filed Critical Sharp Corp
Publication of EP0214824A2 publication Critical patent/EP0214824A2/fr
Publication of EP0214824A3 publication Critical patent/EP0214824A3/en
Application granted granted Critical
Publication of EP0214824B1 publication Critical patent/EP0214824B1/fr
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
    • G11B7/261—Preparing a master, e.g. exposing photoresist, electroforming
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/136—Coating process making radiation sensitive element
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/146—Laser beam

Definitions

  • the present invention relates to an optical memory element capable for at least one of the recording, reroducing and erasing operations by means of optical beam irradiation, or more specifically to an optical memory element substrate and a photo-mask for use in transcribing guide track and track address pattern onto the optical memory element substrate.
  • Optical memory elements can be classified nto the three types in terms of their use: read-only memory, add-on memory and erasable memory.
  • optical memory elements ensure high density and large capacity because a bit (information recording unit), which is determined solely by the optical beam diameter, can be made as small as about 1 ⁇ m in size. This fact, however, causes a number of restrictions on an optical memory system; optical beam positioning must be extremely accurate in order to record information precisely in a predetermined point or reproduce proper information recorded in a preselected point.
  • address data can be recorded together with data information so that it is possible to properly position the optical beam while recorded data information is being reproduced.
  • add-on memory or erasable memory type on the other hand, it is difficult to record address data together with data information in the memory. Therefore, in the add-on memory or the erasable memory, guide signals or guide addresses are normally recorded on the memory substrate.
  • an optical memory element to be used as add-on or erasable memory normally has guide tracks in the substrate, to guide information-recording or -reproducing beam spot to a specified position on the optical memory element.
  • track address-indicating data is written in a part of each guide track to locate the guide track.
  • Fig. 1 shows the essential part of the memory substrate of the add-on or erasable memory in perspective view.
  • stripe-shaped grooves are formed in the substrate, and information is recorded or reproduced along the grooves.
  • the grooves are intermittent in the circumferential direction so as to provide address bit information of each groove.
  • guide tracks 3 and track address portion 2 (together with sector address if the tracks are divided into many sectors) are formed concentrically or spirally in the substrate 1. For the purpose of simplicity, only one track 3 and only one address portion 2 are shown in Fig. 2.
  • a number of methods have been practised for manufacturing a disc substrate provided with tracks and addresses as described above.
  • a mask which carries guide tracks and addresses thereon may be airtightly placed on a resist film applied on a disc glass, to form the tracks and addresses in form of grooves or pits directly on the disk glass.
  • it is essential to form the guide tracks in such a manner that the guide track centre coincides with the centre hole of the disc glass as precisely as possible.
  • With poor concentricity between the guide tracks and the disc glass when the disc glass is rotated for recording, reproduction or erasure with the centre hole fixed on a rotary shaft 4, as shown in Fig.
  • the guide tracks vibrate significantly with respect to a recording, reproducing or erasing laser beam 5, hampering track servo operation for controlling the lens position.
  • the above manufacturing method can cause another problem in the guide track and track address pattern transcription process.
  • the resist film 6, when applied, tends to have a partial rise 8 at the peripheral portion of the disc glass as shown in Fig. 4.
  • This rise 8 often impairs close contact between the resist film 6 and the photo-mask 7, although it is desirable that they are made in close contact with each other.
  • the width of this deficient close contact is usually 1 ⁇ 2mm.
  • the guide track and address pattern on the photo mask 7 is omitted. The deficiency in close contact prevents the guide tracks and track addresses from being formed at proper positions.
  • Co-pending European patent application EP-A2-0155000 by the present applicants discloses a method for manufacturing an optical memory element, comprising the steps of: providing a disc-shaped substrate; disposing a resist film on said substrate; providing a photo-mask carrying a guide groove pattern on the resist film; forming a guide groove pattern latent image on said resist film; developing said guide groove pattern latent image formed on said resist film; conducting an etching operation through said developed guide groove pattern so as to form guide grooves in said substrate; removing said resist film from said substrate; and disposing a recording medium layer on said substrate having said guide grooves formed therein.
  • an optical memory element in which guide track and track addresses are accurately formed on the substrate of the optical memory element; to provide a method for manufacturing an optical memory element, which method ensures accurate formation of guide tracks and track addresses; to provide a mask which facilitates coincidence between the guide track centre and the disc centre hole when transcribing guide tracks and addresses on a resist film applied on the disc; to provide a photo-mask which prevents deficient close contact between a resist film and the photo-mask from being caused by a rise of the resist film on the peripheral portion of the disc glass; and to provide an improvement in the configuration of a glass substrate so as to achieve guide tracks and address-indicating grooves of more accurate shape.
  • said substrate has a hole in the centre thereof and said photo-mask has a marker of a shape corresponding to said centre hole in the substrate and a pattern for guide tracks to be transcribed onto the optical memory element, said marker and said pattern having been formed on said photo-mask simultaneously, thereby to facilitate centring of the resulting transcribed guide tracks on said optical memory element.
  • a cut-away portion is preferably preliminary formed in said photo-mask at a position facing a rise of said resist film.
  • the peripheral end portion of said substrate is ground to be inclined so that a rise of the resist film which is formed at the peripheral edge of the substrate when applied on the substrate is lower than the plane of the substrate portion where the guide grooves are formed.
  • the peripheral portion of the substrate may be ground to be inclined so that the plane of the substrate with the grooves formed therein is higher than the rise of the resist film which can occur on the peripheral portion of the substrate when the resist film is applied on the substrate.
  • Fig. 1 is a perspective view of the essential part of a glass substrate of an add-on memory or erasable memory after grooves have been formed thereon;
  • Fig. 2 is a perspective view of a typical optical memory element (optical disc);
  • Fig. 3 is a sectional view showing a part of the optical disc system;
  • Fig. 4 is a sectional view showing the contact between the glass substrate and the photo-mask of the conventional optical memory element;
  • Fig. 5 is a sectional view for explaining manufacturing steps of an optical memory element of the present invention;
  • Fig. 1 is a perspective view of the essential part of a glass substrate of an add-on memory or erasable memory after grooves have been formed thereon;
  • Fig. 2 is a perspective view of a typical optical memory element (optical disc);
  • Fig. 3 is a sectional view showing a part of the optical disc system;
  • Fig. 4 is a sectional view showing the contact between the glass substrate and the photo-mask of
  • FIG. 6 is a plan view of an embodiment of an optical disc photo-mask of the present invention
  • Fig. 7 is a plan view showing a part of another embodiment of an optical disc photo-mask of the present invention
  • Fig. 8 is a partially enlarged sectional view of another embodiment of an optical disc photo-mask of the present invention
  • Fig. 9 is a sectional view showing the entire photo-mask of Fig. 8
  • Figs. 10 (a) and 10 (b) are partially enlarged sectional veiws showing other embodiments of an optical memory element photo-mask of the present invention
  • Fig. 11 is also a partially enlarged sectional view showing still another embodiment of an optical memory element photo-mask of the present invention
  • FIGS. 12 (a) and 12 (b) are a plan view and a sectional view, respectively, of the glass substrate for an optical memory element;
  • Figs. 13 (a), 13 (b) and 13 (c) are partially enlarged sectional views of glass substrates for an optical memory element of the present invention;
  • Figs. 14 (a), 14 (b) and 14 (c) are partially enlarged sectional views of the optical memory element glass substrates on which resist film is applied.
  • Fig. 5 shows manufacturing steps of the substrate of the optical memory element of the present invention. Referring to Fig. 5, manufacturing method of the optical memory element substrate is described by steps.
  • An optical memory element glass substrate which is highly reliable with respect to oxygen and moisture penetration (or which does not admit oxygen and moisture penetrations) is cleaned.
  • a photo resist film 6 is applied on the glass substrate 1 (See Fig. 5 (a)).
  • the thickness of the photo resist film 6 is preferably about 100nm ⁇ 500nm.
  • a mask plate 7 on which guide truck and address information have been patternized is placed airtightly over the photo resist film 6 on the glass substrate 1. Then, the mask plate 7 is irradiated with ultraviolet ray A to transcribe the mask pattern of the mask plate 7 onto the photo resist film 6 (See Fig. 5 (b)). Since the optical memory element is of disc shape, it is desirable that the mask plate 7 is round.
  • the photo resist film 6 with the mask pattern thereon is developed so as to form grooves in the resist film 6 (See Fig. 5 (c)).
  • the glass substrate 1 covered with the photo resist film 6 having grooves formed therein is subjected to wet etching operation or dry etching operation such as sputtering (reactive ion etching) in an etching gas atmosphere such as CF4 or CHF3. Grooves 8' are then formed in the glass substrate 1 (See Fig. 5 (d)).
  • the developed resist film 6 is removed from the glass substrate 1 by means of sputtering in the O2 atmosphere, or dissolving in a solvent such as acetone. In this way, the glass substrate 1 with the grooves 8' formed therein is produced (See Fig. 5 (e)).
  • a recording medium layer is formed on the glass substrate 1 having the grooves 8 formed therein.
  • the glass substrate 1 having grooves for guide tracks and guide address information is completed through the above process.
  • the mask plate 7 with the pattern for guide tracks and guide address information thereon, prepared in advance, is placed airtightly over the glass substrate 1 coated with the photo resist film 6, so as to transcribe the mask pattern of the mask plate 7. Therefore, the time required for transcribing the guide pattern can be substantially reduced.
  • optical disc mask 7 used in the above manufacturing process is described in the following.
  • Fig. 6 is a plan view of an embodiment of an optical disc mask of the present invention.
  • the mask 7 has been produced by forming Cr or CrO film over, say, a quartz glass disc plate and etching the film to make the pattern shown in Fig. 6.
  • the shaded part indicates the area where Cr or CrO remains unremoved.
  • "a" is an information area in a part of which are formed tracks 3 and addresses 2 spirally or concentrically.
  • Cr or CrO is removed in the area "b" of the mask 7.
  • a positioning reference marker C is provided in the area "b".
  • the concentricity with the tracks can be secured by recording the reference marker C and the guide tracks simultaneously by using the same recording device. For example, when the marker C has virtually the same diameter as the glass disc centre hole, the marker C can be easily adjusted to the disc centre hole when placing the mask on the glass disc for pattern transcription, so that it is easy to achieve the concentricity of the tracks with the disc.
  • the marker need not be limited to the above embodiment.
  • two markers C may be recorded at an interval of about 10 ⁇ 20 ⁇ m and with such diameters that the glass disc centre hole is positioned between the two markers.
  • the glass disc centre hole is about 15mm in diameter, for instance, the two markers may have the diameters of about 14.09mm and 15.01mm, respectively.
  • the centre hole of a glass disc has a high degree of roundness but often differs in the diameter, for instance within the range of about 15 ⁇ 0.5mm, depending upon the manufacturing process.
  • a plurality of markers C with different diameters may be formed concentrically on a mask so that the same mask can be used for discs with different centre hole diameters.
  • the marker C of Fig. 6 it is possible to use the area "b" as a marker if the area "b" is made narrower.
  • Cr or CrO is used in the shaded area of Fig. 6, although clearly another metal film such as Ni, Ti or Ta may be used in place of Cr or CrO.
  • the mask of the present invention it is possible to improve the concentricity of the memory disc guide track with the memory disc center hole, thus minimizing vibration of the guide track with respect to the optical beam in recording, reproducing or erasing information on the disc. Consequently, servo operation of an objective lens for condensing a laser beam becomes easy.
  • Fig. 8 is a partially enlarged sectional veiw of another embodiment of an optical memory element photo mask of the present invention. As shown, a groove 9 is formed in the photo-mask 7 at the position facing the peripheral portion of the glass disc 1, to accommodate the rise 8 of the resist film 6, thus eliminating deficient close contact between the glass disc 1 and the photomask 7.
  • the groove desirably has the width "Y" (about 4mm for example) with the inside diameter of a circle defined by the groove being "X" (127mm for example) as shown in Fig. 9.
  • the depth "Z" of the groove should be about 0.2 ⁇ 0.5mm.
  • the section of the groove is not necessarily square as shown in Fig. 9. It may be triangular as shown in Fig. 10 (a) or semi-circular as shown in Fig. 10 (b).
  • the groove provided in the photo mask may be of any shape as long as it can absorb the rise 8 of the resist film 6 on the periphery of the glass disc 1. In this sense, instead of forming a groove, the peripheral portion 10 of the photo-mask 7 may be made thinner than the central portion as shown in Fig. 11, to absorb the rise 8 of the resist film 6.
  • the guide track and track address pattern for an optical memory element can be properly transcribed onto the resist film applied on the optical memory element substrate.
  • Fig. 12 (a) is a plan view of the glass disc substrate 1 and Fig. 12 (b) is a sectional view of the glass disc substrate 1.
  • the outer edges 15 of the glass disc substrate 1 are chamfered, as shown.
  • Fig. 13 is an enlarged sectional view of the chamfered edge 15.
  • Fig. 13 (a) is a sectional view of the chamfered edge of the conventional glass disc substrate
  • Figs. 13 (b) and 13 (c) are sectional views showing the chamfered edge configuration of the glass disc substrate of the present invention.
  • the surface portion 17 without guide grooves is ground to be lower than the glass disc substrate surface plane 18.
  • Figs. 14 (a), 14 (b) and 14 (c) are sectional views of the glass disc substrates having the edges shown in Figs. 13 (a), 13 (b) and 13 (c), respectively, on which resist film is applied by the spin coat method. At the edge of the glass disc substrate, the resist film has a rise 8 due to the surface tension.
  • the rise 8 of the resist film 6 is higher than the resist film surface plane 11.
  • the mask plate 7 will be positioned on the plane 11', resulting in defective contact over a large area between the mask plate 7 and the resist film 6.
  • the rise 8 of the resist film 6 is lower than the resist film surface plane 11 so that the mask plate 7 can be positioned on the resist film surface plane 11. Consequently, sufficient contact can be obtained between the mask plate 7 and the resist film 6 over the area 16 with the guide grooves formed thereon.
  • the guide grooves formed in the optical memory element are entirely of proper shape, thus reducing noise in reproduced signals.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Optical Record Carriers (AREA)

Claims (3)

  1. Procédé de fabrication d'un élément de mémoire optique, comprenant les opérations consistant à prévoir un substrat en forme de disque (1), à disposer un film de résist (6) sur ce substrat, à prévoir un photomasque (7) portant un motif de rainures pilotes situé sur le film de résist, à former une image latente du motif de rainures pilotes sur le film de résist, à développer cette image latente du motif de rainures pilotes formée sur le film de résist, à exécuter une opération d'attaque à travers le motif de rainures pilotes développé, de façon à former des rainures pilotes dans le substrat, à retirer le film de résist du substrat et à disposer une couche de milieu d'enregistrement sur ce substrat dans lequel sont ménagées les rainures pilotes, procédé selon lequel le substrat présente un trou en son centre et le photomasque comporte un élément de marquage (C) d'une forme correspondant à ce trou central du substrat et un motif de rainures pilotes (3) devant être transcrit sur l'élément de mémoire optique, cet élément de marquage et ce motif ayant été formés en même temps sur le photomasque, de façon à faciliter ainsi un centrage des rainures pilotes transcrites (3),obtenues, sur l'élément de mémoire optique.
  2. Procédé suivant la revendication 1, selon lequel une partie découpée (9) est formée au préalable dans le photomasque en un emplacement faisant face à une surépaisseur (8) du film de résist.
  3. Procédé suivant la revendication 1, selon lequel la partie périphérique extrême (10) du substrat est usinée de manière à être inclinée, de telle façon qu'une surépaisseur (8) du film de résist qui est formée à l'endroit du bord périphérique de ce substrat, lorsque le film est appliqué sur le substrat, soit plus basse que le plan de la partie du substrat dans laquelle les rainures pilotes sont formées.
EP19860306711 1985-08-30 1986-08-29 Procédé de fabrication d'un elément de mémoire optique Expired EP0214824B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP192937/85 1985-08-30
JP19293785A JPS6252741A (ja) 1985-08-30 1985-08-30 光ディスク基板用マスク
JP60207864A JP2534226B2 (ja) 1985-09-19 1985-09-19 光メモリ素子用フオトマスク
JP207864/85 1985-09-19
JP215909/85 1985-09-26
JP60215909A JPS6273440A (ja) 1985-09-26 1985-09-26 光メモリ素子

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP90203177.2 Division-Into 1990-12-03

Publications (3)

Publication Number Publication Date
EP0214824A2 EP0214824A2 (fr) 1987-03-18
EP0214824A3 EP0214824A3 (en) 1988-07-27
EP0214824B1 true EP0214824B1 (fr) 1991-12-18

Family

ID=27326691

Family Applications (2)

Application Number Title Priority Date Filing Date
EP19860306711 Expired EP0214824B1 (fr) 1985-08-30 1986-08-29 Procédé de fabrication d'un elément de mémoire optique
EP90203177A Expired - Lifetime EP0434114B1 (fr) 1985-08-30 1986-08-29 Elément de mémoire optique et son procédé de fabrication

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP90203177A Expired - Lifetime EP0434114B1 (fr) 1985-08-30 1986-08-29 Elément de mémoire optique et son procédé de fabrication

Country Status (3)

Country Link
US (2) US4925776A (fr)
EP (2) EP0214824B1 (fr)
DE (2) DE3682985D1 (fr)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0155000B1 (fr) * 1984-03-16 1991-08-14 Sharp Kabushiki Kaisha Méthode de fabrication d'un élément de mémoire optique
DE3682985D1 (de) * 1985-08-30 1992-01-30 Sharp Kk Verfahren zur herstellung eines optischen verzeichniselementes.
CA1313792C (fr) * 1986-02-28 1993-02-23 Junji Hirokane Methode de fabrication de photomasques et photomasque fabrique selon cette methode
JPH0770094B2 (ja) * 1987-12-04 1995-07-31 シャープ株式会社 ディスク状光記録媒体の製造方法および製造用フォトマスク
US4931138A (en) * 1988-01-12 1990-06-05 Olympus Optical Co. Ltd. Method and apparatus for manufacturing optical card
DE4029099A1 (de) * 1990-09-13 1992-04-09 Technics Plasma Gmbh Verfahren zum herstellen von spritzgussmatritzen
JPH04286736A (ja) * 1991-03-15 1992-10-12 Sharp Corp 光メモリ素子のマスター原盤用基板の製造方法
IL123871A0 (en) * 1995-09-29 1998-10-30 Sage Technology Inc Optical digital media recording and reproduction system
US6096405A (en) * 1996-09-30 2000-08-01 Hoya Corporation Magnetic recording medium having a glass substrate and method of manufacturing the magnetic recording medium
US6030513A (en) * 1997-12-05 2000-02-29 Applied Materials, Inc. Full face mask for capacitance-voltage measurements
US6096404A (en) * 1997-12-05 2000-08-01 Applied Materials, Inc. Full face mask for capacitance-voltage measurements
CN1098164C (zh) * 1998-03-04 2003-01-08 大霸电子股份有限公司 喷嘴头墨水舱厚膜曝光对位的方法
JP2001209945A (ja) 2000-01-26 2001-08-03 Sharp Corp 光ディスク及び記録再生装置
US20060018052A1 (en) * 2004-07-23 2006-01-26 Konica Minolta Opto, Inc. Information recording medium glass substrate, information recording medium, information recording apparatus and manufacturing method of information recording medium glass substrate
US9491275B2 (en) * 2005-09-15 2016-11-08 AT&T Intellectual Property I, L.P., by transfer of ownership from AT&T Systems, methods and computer program products for aggregating contact information

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US3824014A (en) * 1973-07-26 1974-07-16 Us Navy Relief mask for high resolution photolithography
US3936301A (en) * 1974-04-01 1976-02-03 Bell Telephone Laboratories, Incorporated Process for contact photolithography utilizing a photomask having indented channels
JPS5182601A (fr) * 1975-01-17 1976-07-20 Sony Corp
JPS5217815A (en) * 1975-07-30 1977-02-10 Fuji Photo Film Co Ltd Substrate and material using the same
US4423137A (en) * 1980-10-28 1983-12-27 Quixote Corporation Contact printing and etching method of making high density recording medium
US4374912A (en) * 1981-03-31 1983-02-22 Dai Nippon Insatsu Kabushiki Kaisha Photomask and photomask blank
JPS58102795A (ja) * 1981-12-16 1983-06-18 Ricoh Co Ltd 光情報記録媒体
US4515877A (en) * 1982-11-27 1985-05-07 Basf Aktiengesellschaft Image-recording materials and image-recording carried out using these to produce an optical mask
JPS59102235A (ja) * 1982-12-03 1984-06-13 Sumitomo Electric Ind Ltd ホトマスク
US4544443A (en) * 1983-05-13 1985-10-01 Shap Kabushiki Kaisha Method for manufacturing an optical memory element
JPH0636253B2 (ja) * 1983-08-18 1994-05-11 シャープ株式会社 光メモリ円板
JPS6085724U (ja) * 1983-11-17 1985-06-13 シャープ株式会社 光メモリ円板
EP0155000B1 (fr) * 1984-03-16 1991-08-14 Sharp Kabushiki Kaisha Méthode de fabrication d'un élément de mémoire optique
JPH0648546B2 (ja) * 1984-07-14 1994-06-22 日本ビクター株式会社 情報記録担体の製造法
JPS6195356A (ja) * 1984-10-16 1986-05-14 Mitsubishi Electric Corp フオトマスクブランク
DE3682985D1 (de) * 1985-08-30 1992-01-30 Sharp Kk Verfahren zur herstellung eines optischen verzeichniselementes.

Also Published As

Publication number Publication date
EP0434114B1 (fr) 1994-01-26
DE3689593T2 (de) 1994-06-16
US4925776A (en) 1990-05-15
EP0214824A3 (en) 1988-07-27
EP0214824A2 (fr) 1987-03-18
US5470694A (en) 1995-11-28
EP0434114A1 (fr) 1991-06-26
DE3689593D1 (de) 1994-03-10
DE3682985D1 (de) 1992-01-30

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